Dinosaurs

Dinosaurs are a diverse group of animals that were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous. Also; you will find a lot of random extinct reptiles being posted here that aren't technically "dinosaurs" (not included in the superorder), but are from the Mesozoic era.

[eartharchives]

'Frankenstein dinosaur' mystery solved

A dinosaur that seemed to be an evolutionary mishmash turns out to have a key place in history.

[edwardspoonhands]

We couldn’t possibly know the answer to this question…right? WRONG.

[spacetimewithstuartgary]

Why Tyrannosaurus was a slow runner

…and why the largest are not always the fastest

No other animal on land is larger than an elephant - but the fastest runner is the medium-sized cheetah.

A research team under the direction of the German Centre for Integrative Biodiversity Research (iDiv) and the Friedrich Schiller University Jena have now described why the largest animals are not the fastest.

They have managed to so thanks to an amazingly simple mathematical model. The only information that the model must ‘be fed’ with is the weight of a particular animal as well as the medium it moves in, so either land, air or water. On this basis alone, it calculates the maximum speed that an animal can reach with almost 90% accuracy.

“The best feature of our model is that it is universally applicable,” says the lead author of the study, Myriam Hirt of the iDiv research centre and the University of Jena. “It can be performed for all body sizes of animals, from mites to blue whales, with all means of locomotion, from running and swimming to flying, and can be applied in all habitats.” Moreover, the model is by no means limited to animal species that currently exist, but can be applied equally well to extinct species.

“To test whether we can use our model to calculate the maximum speed of animals that are already extinct, we have applied it to dinosaur species, whose speed has up to now been simulated using highly complex biomechanical processes,” explains Hirt.

The result is that the simple model delivered results for Triceratops, Tyrannosaurus, Brachiosaurus and others that matched those from complex simulations - and were not exactly record-breaking for Tyrannosaurus, who reached a speed of only 27 km/h (17 mi/h).

“This means that in future, our model will enable us to estimate, in a very simple way, how fast other extinct animals were able to run,” says the scientist.

Two assumptions are the basis of the model. The first assumption is related on the fact that animals reach their maximum speeds during comparatively short sprints, and not while running over long distances. Unlike running over longer distances, where the body constantly resupplies the muscles with energy (aerobic metabolism), sprinting uses energy that is stored in the muscles themselves but which is exhausted relatively quickly (anaerobic metabolism).

It seems logical enough: the larger the animal, the more muscle it has - and thus the faster it can sprint. However, Newton’s laws of motion also apply in the animal kingdom, we know mass has to overcome inertia, and so a five-tonne African elephant simply cannot start moving as quickly as a 2.5-gramme Etruscan shrew.

By the time large animals such as the elephant get up to full speed while sprinting, their rapidly available energy reserves also soon run out. Taken together, these two assumptions result in the previously mentioned curve: A beetle is slower than a mouse, which is slower than a rabbit, which is slower than a cheetah - which is faster than an elephant.

TOP IMAGE….Tyrannosaurus Rex meaning “tyrant lizard king”, is a genus of coelurosaurian theropod dinosaur.

UPPER IMAGE….The African elephant is the largest animal on land, but not the fastest. Credit Bernd Adam

CENTRE IMAGE….There is a parabola-like relationship between the body mass of animals and the maximum speed they are able to reach. For the first time, researchers are able to describe how this comes about, thanks to a simple mathematical model. Credit Myriam Hirt

LOWER IMAGE….The new model also provides results for extinct species which agree with the results produced by highly complex biomechanical simulations. Credit Myriam Hirt

BOTTOM IMAGE….Like other tyrannosaurids, Tyrannosaurus was a bipedal carnivore with a massive skull balanced by a long, heavy tail. Relative to its large and powerful hind limbs, Tyrannosaurus fore limbs were short but unusually powerful for their size and had two clawed digits. The most complete specimen measures up to 12.3 m (40 ft) in length, up to 3.66 meters (12 ft) tall at the hips, and according to most modern estimates 8.4 metric tons (9.3 short tons) to 14 metric tons (15.4 short tons) in weight.

[paleotopresent-deactivated20210]

Smilodon fatalis

[paleotopresent-deactivated20210]

QUETZALCOATLUS

Quetzalcoatlus goes down in history as the largest flying organism of all time, with a wingspan of 12 metres, which is larger than some planes. Quetzalcoatlus was the undisputed king of the Late cretaceous skies, so it seems fitting that its name is derived from an Aztec god, Quetzalcoatl. Although its wingspan is impressive, Quetzalcoatlus also had a huge 2.5 metre long skull, that is the average height of an Asian elephant! To get such a huge animal in the air, a complex system of air sacs was needed inside the bones, this meant that Quetzalcoatlus probably weighed no more than 250kg. Quetzalcoatlus, along with many pterosaurs, was originally thought to spend most of its time gliding over the oceans, skimming fish out from the surface of the water with their elongated beaks. However, due to the skull and beak morphology and the presence of fossils far inland it has become more widely accepted that Quetzalcoatlus stalked prey far below on the land. The fore and hind limb morphology of Quetzalcoatlus also suggests that they were competent walkers on the land, they would have stood up to 3 metres tall. 

The feeding habits of Quetzalcoatlus still remain something of a mystery. It was originally thought to be more of a scavenger, but the blunt beak was unsuited to stripping and picking flesh of a bony creature. It is more likely that Quetzalcoatlus hunted like modern-day storks, stalking the land from the skies above for smaller animals and then swooping down to eat them whole.

[rhade-zapan]

Artist Unknown

Follow Rhade-Zapan for more visual treats

[asapscience]

This kind of preservation is largely found in dinosaur fossils within the Jurassic Morrison Formation, a sedimentary rock formation found in Wyoming, Utah and Colorado. [Image via http://imgur.com/gallery/2OFmi]

[carnegiemuseumnaturalhistory]

Dinosaur eggs! These fossilized eggs are part of Carnegie Museum of Natural History’s hidden collection in the Section of Vertebrate Paleontology. 

[coolthingoftheday]

On December 25th of 2015, a farmer, who was out on his land, found what he thought was an unusual rock. Jose Antonio Nievas made the find near a stream on his farm in Carlos Spegazzini, a town located about twenty miles from Buenos Aires, Argentina. He found the object partly covered in mud and dug around it to find out what it was.

It turned out that the mysterious rock-like object wasn’t what he expected - and when he realized the significance of his discovery, he decided to get people from the scientific community involved. What he had dug up wasn’t a rock at all - it was an extremely rare type of fossil. After reviewing it, scientists agreed that the object was not a rock, a meteorite or dinosaur egg, but the shell of a glyptodon, a large, armored mammal that lived during the Pleistocene epoch, and were the ancestors of the modern-day armadillo. Glyptodons could weigh up to two tonnes, and probably coexisted with humans for about 4,000 years before going extinct. 

[nathan-e-rogers]

Euthycarcinoid - First Footsteps On Land

My illustration of an Euthycarcinoid, a type of early arthropod that may have been the first organisms to set foot (or perhaps more accurately, lots of little feet) on dry land as far back as the Cambrian Period, 530 million years ago.

Life’s colonization of land may have been made possible by the formation of Earth’s protective ozone layer - read more at Earth Archives:

http://www.eartharchives.org/articles/life-on-land-made-possible-by-ozone-layer/

Also check out this Nature news article on the first land footprints:

http://www.nature.com/news/2002/020429/full/news020429-2.html

[nathan-e-rogers]

Murusraptor barrosaensis 

Late Cretaceous, Patagonia

Murusraptor is a newly-described megaraptoran theropod dinosaur from the Sierra Barrosa Formation in Argentina. Adult Murusraptor are estimated to have grown to over 6.4 m (21 ft) in length. There are competing hypotheses about the position of the Megaraptora (the clade to which Murusraptor belongs) within the larger group Theropoda, and in the future more complete specimens may help to answer this question.

Read more about this new discovery at Earth Archives:

http://www.eartharchives.org/articles/murusraptor-a-megaraptoran-theropod-from-the-late-cretaceous-of-patagonia/

[nathan-e-rogers]

Edmontosaurus annectens

Maastrichtian Age of the Late Cretaceous, North America

One of the best-known dinosaurs, Edmontosaurus “mummies” have been found with skin imprints, giving scientists an unusually detailed view of how they may have looked in life. Edmontosaurus annectens shared habitat with Tyrannosaurus in the final age of dinosaurs, and may have been the largest of the hadrosaurs (popularly referred to as “duckbills”). Synonymous with Anatosaurus and Anatotitan (among others), Edmontosaurus appears in the forthcoming video game Saurian (referred to there as Anatosaurus).

Read more about this dinosaur at Earth Archives!

[mcblackneck]

Problably my biggest project concerning watercolor. I made several medium sized pictures seperately and photographed them and put them together in photoshop so it’s not perfect. The wing got messed up but I’ll fix that in the future.

[starmaki]

Sue what big teeth you have! #chicago #field museum #sue #dinosaur

[dinosaur-discourse]

whaddyou think dinosaurs fighting was like? and also if you approached a triceratops cautiously enough could you pet it without getting gored?

Let me answer the easier question first: I would not advise attempting to approach a Triceratops.  Just because it’s herbivorous doesn’t mean it’s a peaceful animal; after all hippos kill more people in Africa each year than crocodiles and lions combined.  Also, keep in mind that no one is really sure how keen or dull Triceratops’ senses were; it might have been able to smell you as you approached, or it might have mistaken you for a predator from a distance, and either of these things could lead to the animal charging or otherwise attempting to fight you off.  I would heavily advise against it.

Now then: Dinosaur fights.

Dinosaurs are probably more famous for fighting than any other group of animal - likely due to their perception as “monsters” rather than real animals.  Unlike common reconstructions of dinosaurs, modern animals don’t spend most of their time roaring at one another with their fangs bared, and it’s likely that dinosaurs didn’t either.

However, that’s not to say that dinosaurs never fought with one another.  As predators and prey animals, numerous species of dinosaur definitely clashed with one another on a regular basis - and in some cases, there’s fossil evidence to prove it.  I could probably spend pages and pages on this topic, but… I’m not going to.  Here’s a few of the more famous ones.

Above is one of the world’s most famous dinosaur fossils: a Velociraptor and a Protoceratops, which died and fossilized while locked in combat.  The Velociraptor is in the midst of piercing the Protoceratops’ throat with its toe claw, while the Protoceratops bites down on its arm with its powerful beak.  This fossil proves that these two animals came into conflict.  (However, it doesn’t necessarily prove that Velociraptor preyed on Protoceratops; these two animals may have been fighting for any number of reasons.)

What about these animals’ larger relatives, Tyrannosaurus and Triceratops?  Those two dinosaurs are some of the most iconic combatants of the Mesozoic world, and have been depicted in combat hundreds of times, such as in the reconstruction above.  But was this really the case?

Fossilized Tyrannosaurus stomach contents and heavily damaged Triceratops bones indicate that Triceratops was indeed a prey animal for Tyrannosaurus, and Tyrannosaurus tooth marks present on Triceratops skulls indicate that these animals did get into head-on fights with one another.  (Amazingly, many of these tooth marks began to heal before the Triceratops’ deaths, suggesting that they overpowered or escaped their would-be predators.)

In addition, some species of ceratopsians are known to have fought with each other.  Many Triceratops specimens possess wounds on their horns and frills consistent with intra-specific combat - that is, with fighting amongst themselves.  It’s not certain why this might have been; perhaps male Triceratops would lock horns in competition over mates, like many modern horned animals.  (However, this was not a universal ceratopsian behavior; Centrosaurus, for example, has much lower rates of such wounds, implying that they did not butt heads with one another.)

Some dinosaurs were famous for their weaponry.  One such group includes the ankylosaurids, distinguished from other groups of ankylosaurs - the nodosaurids and polacanthids - by the presence of large, bony clubs on their tails.  The flexible tails of ankylosaurids were capable of generating huge amounts of impact force, possibly enough to break the limbs of would-be attackers.  (They may also have been used for intra-specific combat, but given that ankylosaurids were not prone to injuries, evidence for this is scant.)

Stegosaurs are also well known for their weaponry - in this case, an arrangement of spikes at the end of the tail, known scientifically as the thagomizer.  While once thought to have been only suitable for display, the tail spikes of stegosaurs have since been studied in greater detail, and have often been found to possess signs of combat-related trauma.  In addition, an Allosaurus vertebrae has been found possessing a puncture wound that perfectly fits a Stegosaurus tail spike.

I’m kind of against depictions of dinosaurs that show them doing nothing but fighting.  After all, modern animals spend most of their time coexisting peacefully; combat scenarios are the exceptions rather than the rules, despite what paleoart so often likes to illustrate.  However, I can’t blame paleoartists for depicting it so often.  As some of Earth’s most titanic creatures, the idea of dinosaurs fighting is very exciting - and based on current fossil evidence, it certainly did happen.

[saurian-game]

Fresh animations for our newly released Tyrannosaurus.  We are all extremely proud of this design and are pleased to show you guys the fruits of our labor.

[arvalis]

Hey guys look at this, our new T. rex design in motion.  I’m totally and completely unbiased, but damn its real pretty.  Those animations are just so buttery smooth.

[thek560]

Carnotaurus by Thek560

Carnataurus was a medium sized theropod that lived 70 million years ago in what is now South America.